It is known that, in a standard flight management system, in particular of the FMS (“Flight Management System”) type, each flight plan is initialized independently. The predictions which are therefore carried out on a subsequent flight plan do not depend on the state of the flight which precedes it. Thus, for two (or more) successive flights, with no refueling between the flights, there is an uncertainty regarding the second flight. Specifically, the conditions encountered during the first flight (wind, unscheduled change of route, etc) may strongly influence the consumption of fuel on completion of this first flight, and hence the fuel available for the next flight. Likewise, the flight time for the first flight may be influenced by various events, and this may possibly modify the departure time of the next flight.
Such effects are significant especially in the case of military aircraft which perform a series of successive flights without refueling during the various stops (for example connecting flights between airbases).
Consequently, with a standard flight management system such as this, the pilot of the aircraft must carry the predictions relating to the first flight over to the initial conditions of the next flight, and must do so very regularly so as to take account of alterations in the conditions encountered during this first flight. This mode of operation therefore makes it necessary to carry out in-flight manipulations on the next flight, thereby increasing in particular the workload of the pilot or of the crew of the aircraft.